FIBROUS MATERIAL IMPREGNATED WITH THERMOPLASTIC POLYMER

Abstract

An impregnated fibrous material comprising a fibrous material made of continuous fiber and at least one thermoplastic polymer matrix, wherein the at least one thermoplastic polymer is an non-reactive amorphous polymer, the glass transition temperature of which is such that Tg80 C., or a non-reactive semi-crystalline polymer, the melting temperature of which is Tf150 C., the fiber volume ratio is constant in at least 70% of the volume of the tape or ribbon, the fiber ratio in the pre-impregnated fibrous material ranging from 45 to 65% by volume, the porosity rate in the pre-impregnated fibrous material being less than 10%.

Claims

1.-20. (canceled)

21. An impregnated fibrous material comprising a fibrous material of continuous fibers and at least one thermoplastic polymer matrix, wherein at least one thermoplastic polymer is a non-reactive amorphous polymer whose glass transition temperature is such that Tg80 C., or a non-reactive semi-crystalline polymer whose melting temperature is Tf150 C., where Tg and Tf are determined by differential scanning calorimetry (DSC) according to standard 11357-2:2013 and 11357-3:2013 respectively, the fiber content by volume is constant in at least 70% of the volume of the web or ribbon, the fiber content in said prepreg fiber material being between 45 and 65% by volume on both sides of said fiber material, the porosity rate in said prepreg fiber material being less than 10%, said impregnated fibrous material being free of non-reactive liquid crystal polymers (LCP), wherein the number average molecular weight (Mn) changes by less than 50% during its implementation, said impregnated fibrous material being monolayer, the impregnation being carried out with at least one expansion.

22. The impregnated fibrous material according to claim 21, wherein said material is not flexible.

23. The impregnated fibrous material according to claim 21, wherein the number of fibers in said fibrous material for carbon fibers is greater than or equal to 30K or the weight for glass fiber is greater than or equal to 1200 Tex.

24. The impregnated fibrous material according to claim 21, wherein at least one thermoplastic polymer is selected from: polyaryl ether ketones (PAEK); polyaryl ether ketone ketone (PAEKK; aromatic polyether imides (PEI); polyaryl sulfones; polyarylsulfides; polyamides (PA); PEBAs; polyolefins; and mixtures thereof.

25. The impregnated fibrous material according to claim 21, wherein the at least one thermoplastic polymer is selected from polyamides, PEKK, PEI and a mixture of PEKK and PEI.

26. The impregnated fibrous material according to claim 25, wherein said polyamide is selected from aliphatic polyamides, cycloaliphatic polyamides and semi-aromatic polyamides (polyphthalamides).

27. The impregnated fibrous material according to claim 26, wherein said aliphatic polyamide is selected from polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11/1010, polyamide 12/1010, or a mixture thereof or a copolyamide thereof, and the block copolymers, and said semi-aromatic polyamide, is a semi-aromatic polyamide, optionally modified with urea units selected from an MXD6 and an MXD10 or a semi-aromatic polyamide of formula X/YAr, selected from a semi-aromatic polyamide of formula A/XT in which A is selected from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine).(Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36, the unit (Ca diamine) being selected from aliphatic diamines, linear or branched, cycloaliphatic diamines and alkylaromatic diamines and the unit (Cb diacid) being chosen from aliphatic, linear or branched diacids, cycloaliphatic diacids and aromatic diacids; X.T denotes a unit obtained from the polycondensation of a Cx diamine and terephthalic acid, with x representing the number of carbon atoms of the Cx diamine, x being between 6 and 36, T corresponding to terephthalic acid, MXD corresponding to m-xylylene diamine.

28. The impregnated fibrous material according to claim 21, wherein said fibrous material comprises continuous fibers selected from carbon, glass, silicon carbide, basalt, silica, flax or hemp, lignin, bamboo, sisal, silk, or cellulose, or amorphous thermoplastic fibers with a glass transition temperature Tg higher than the Tg of said polymer or said polymer mixture when the latter is amorphous or higher than the Tf of said polymer or said polymer mixture when the latter is semi-crystalline, or the semi-crystalline thermoplastic fibers with a melting temperature Tf higher than the Tg of said polymer or said polymer mixture when the latter is amorphous or higher than the Tf of said polymer or said polymer mixture when the latter is semi-crystalline, or a mixture of two or more of said fibers.

29. The impregnated fibrous material according to claim 21, wherein said thermoplastic polymer further comprises carbonaceous fillers.

30. A method of using the impregnated fibrous material, as defined in claim 21, for the preparation of calibrated ribbons suitable for the manufacture of three-dimensional composite parts by automatic application of said ribbons by means of a robot.

31. A ribbon comprising at least one fibrous material as defined in claim 21.

32. The ribbon according to claim 31, wherein it is made of a single unidirectional ribbon or a plurality of parallel unidirectional ribbons.

33. The ribbon according to claim 31, wherein it has a width (I) and a thickness (ep) suitable for robot application in the manufacture of three-dimensional workpieces, without the need for slitting, the width (I) being of at least 5 mm and up to 400 mm.

34. The ribbon according to claim 32, wherein the thermoplastic polymer is a polyamide selected from an aliphatic polyamide PA 6, PA 11, PA 12, PA 66, PA 46, PA 610, PA 612, PA 1010, PA 1012, PA 11/1010 or PA 12/1010 or a semi-aromatic polyamide selected from a PA MXD6 and a PA MXD10 or chosen from PA 6/6T, PA 61/6T, PA 66/6T, PA 11/10T, PA 11/6T/10T, PA MXDT/10T, PA MPMDT/10T, PA BACT/6T, PA BACT/10T and PA BACT/10T/6T, a PVDF, a PEEK, PEKK and a PEI or a mixture thereof.

35. The ribbon according to claim 34, wherein the thermoplastic polymer is a polyamide selected from an aliphatic polyamide selected from PA 6, PA 11, PA 12, PA 11/1010 or PA 12/1010 or a semi-aromatic polyamide selected from PA 6/6T, PA 61/6T, PA 66/6T, PA 11/10T, PA 11/6T/10T, PA MXDT/10T, PA MPMDT/10T and PA BACT/10T, T corresponding to terephthalic acid, MXD corresponding to m-xylylene diamine, MPMD corresponding to methylpentamethylene diamine and BAC corresponding to bis(aminomethyl)cyclohexane.

36. A method of using the ribbon, as defined according to claim 31, in the manufacture of three-dimensional composite parts.

37. The method according to claim 36, wherein said manufacture of said composite parts relates to the fields of transportation, oil and gas, gas storage, aeronautics, nautical, railways; renewable energies selected from wind energy, hydro turbines, energy storage devices, solar panels; thermal protection panels; sports and leisure, health and medical and electronics.

38. A three-dimensional composite part, wherein it results from the use of at least one unidirectional ribbon of impregnated fibrous material as defined according to claim 31.

Description

DESCRIPTION OF THE FIGURES

[0210] FIG. 1 details a tank (10) comprising a fluidized bed (12) with a supporting part, whose height is adjustable (22). The edge of the tank entry is equipped with a rotating roller 23a on which the roving 21a travels and the edge of the tank exit is equipped with a rotating roller 23b on which the roving 21b travels.

[0211] FIG. 2 presents describes an embodiment with a single compression roller, with a tank (10) comprising a fluidized bed (12) in which a single cylindrical compression roller (24) is present and showing the angle .sub.1.

[0212] The arrows near the fiber indicate the direction of travel of the fiber.

[0213] FIG. 3 presents describes an embodiment with a single compression roller, with a tank (30) comprising a spray gun (31) for powder (32) in which a single cylindrical compression roller (33) is present and showing the angle .sub.1.

[0214] The arrows near the fiber indicate the direction of travel of the fiber.

[0215] FIG. 4 shows a drawing of a three roller-heating system.

[0216] FIG. 5 shows a photo taken with a scanning electron microscope of a section view of a Zoltek, 50K carbon fiber roving impregnated with a PA MPMDT/10T polyamide powder with D50=115 m according to example 1 and described in WO 2015/121583 (before calendaring).

[0217] The method according to WO 2015/121583 leads to a fibrous material which is lacking homogeneity in several areas of the impregnated roving and also a major porosity and a bad distribution of fibers.

[0218] The diameter of one fiber represents 7 m.

[0219] FIG. 6 shows a photo taken with a scanning electron microscope of a cross-section view of a Zoltek, 50K carbon fiber roving impregnated with a PA MPMDT/10T polyamide powder with D50=115 m according to invention example 2 (before calendaring).

[0220] The diameter of one fiber represents 7 m.

[0221] The following examples illustrate the scope of the invention, without limitation.

Example 1 (Comparison Example)

[0222] A roving of Zoltek, 50K carbon fiber was impregnated with PA MPMDT/10T such as described in WO 2015/121583.

[0223] D50=115 m

Results:

[0224] The results are given in FIG. 5 and show a lack of homogeneity in several areas of the impregnated roving and also a major porosity and a bad distribution of fibers.

Example 2: Fibrous Material (Zoltek, 50K Carbon Fiber) Simile Layer, Impregnated with MPMDT/10T

[0225] The following operating mode was executed:

[0226] Four cylindrical and fixed rollers with 8 cm diameter are present upstream from the tank comprising the fluidized bed and the roving travels over them.

[0227] The rollers are 54 cm apart (distance between the first and last roller).

Preimpregnation Step by Fluidized Bed

[0228] A cylindrical compression roller R.sub.1, 25 cm diameter, in the tank (L=500 mm, W=500 mm, H=600 mm). [0229] 0.3 second residence time in the powder [0230] Angle .sub.1 is 25 [0231] D50=115 m, (D10=49 m, D90=207 m) for the MPMDT/10T powder. [0232] Edge of the tank equipped with a fixed roller.

Heating Step

[0233] The heating system used is the one described in FIG. 4, but with eight fixed cylindrical rollers R.sub.1 R.sub.8 with 8 mm diameter.

[0234] The feed speed of the roving is 10 m/min.

[0235] The infrared used has a power of 25 kW; the height between the infrared and the upper roller is 4 cm and the height between the infrared and the lower rollers is 9 cm.

[0236] The angles .sub.1 to .sub.8 are identical and are 25.

[0237] The height h is 20 mm

[0238] The length l is 1000 mm

[0239] The eight rollers are each 43 mm apart.

[0240] Calendaring after the heating step by means of two calendars mounted in series equipped with a 1 kW IR each.

[0241] FIG. 6 shows the resulting impregnated fibrous material.

[0242] The resulting fibrous material is a single layer material which has an impregnation homogeneity and a low porosity with a very good distribution of the fibers.

Example 3: Determination of the Porosity Level by Image Analysis

[0243] The porosity was determined by image analysis on a roving of 50K carbon fiber impregnated by MPMDT/10T in fluidized bed followed by a heating step such as defined above.

[0244] It is under 5%.

Example 4: Determination of the Porosity Level the Relative Difference Between Theoretical and Experimental Density (General Method)

[0245] a) The required data are: [0246] The density of the thermoplastic matrix [0247] The density of the fibers [0248] The grammage of the reinforcement: [0249] linear density (g/m), for example, for a inch tape (coming from a single roving) [0250] surface density (g/m.sup.2) for example, for a wider tape or fabric

[0251] b) Measurements to do:

[0252] The number of samples must be at least 30 so that the result is representative of the material studied. The measurements to be done are: [0253] The dimensions of the samples collected: [0254] Length (if the linear density is known). [0255] Length and width (if the surface density is known). [0256] The experimental density of the samples collected: [0257] Mass measurements in air and in water. [0258] The measurement of the fiber level is determined according to ISO 1172:1999 or by thermogravimetric analysis (TGA) such as determined in the document B. Benzler, Applications Laboratory, Mettler Toledo, Giesen, UserCom 1/2001.

[0259] The measure of the carbon fiber level can be determined according to ISO 14127:2008.

[0260] Determination of the theoretical density from the fiber level:

[0261] a) Determination of the theoretical density from the fiber level:

[00001]$\%.Math..Math.{\mathrm{Mf}}_{\mathrm{th}}=\frac{m_l.Math.L}{{\mathrm{Me}}_{\mathrm{air}}}$

where
m.sub.l the linear density of the tape,
L the length of the sample, and
Me.sub.air the mass of the sample measured in air.

[0262] The variation of the fiber density level is assumed to be directly related to a variation of the matrix level without considering the variation of the quantity of fibers in the reinforcement.

[0263] b) Determination of the theoretical density:

[00002]$d_{\mathrm{th}}=\frac{1}{\frac{1-\%.Math..Math.{\mathrm{Mf}}_{\mathrm{th}}}{d_m}+\frac{\%.Math..Math.{\mathrm{Mf}}_{\mathrm{th}}}{d_f}}$

where d.sub.m and d.sub.f are the respective densities of the matrix and the fibers.

[0264] The theoretical density thus calculated is the achievable density if there are no porosities in the samples.

[0265] c) Evaluation of the porosity:

[0266] The porosity is then the relative difference between theoretical density and experimental density.